An investigation into the antimicrobial effects of adrenomedullin on members of the skin, oral, respiratory tract and gut microflora

Adrenomedullin, a novel vasoactive peptide, is known to be expressed by many surface epithelial cells and it was postulated that this peptide may have a protective role. The objective of the study was to assess the antimicrobial activity of adrenomedullin against members of the human skin, oral, respiratory tract and gut microflora using disc diffusion and broth microdilution assays. All strains of bacteria screened in an agar diffusion assay were sensitive; Gram-positive and Gramnegative bacteria were equally susceptible. No activity against the yeast Candida albicans was observed. In a broth microdilution assay, minimum inhibitory and minimum bacteriocidal concentrations ranged from 7.75 X 10(-4) to 12.5 mu g ml-l and 0.003 to >25.0 mu g ml(-1), respectively. We propose an antimicrobial role for adrenomeduliin, participating in the prevention of local infection, thus contributing to host defence systems. (C) 1999 Published by Elsevier Science B.V. All rights reserved.